I forget where I found this originally (sorry). And I've modified it slightly over the years. But if you're on YouTube in a desktop browser and you'd like to have the video in a small pop-up window, tap this bookmarklet and it automatically creates the perfectly sized window for you.
- Create a new bookmark with any URL.
- Edit that bookmark in your browser, delete the URL that is there, and paste the code you see in the JS file into the Location field.
You're welcome / Colin